A series of magnesium-rich Mg-Al spinels were prepared from hydrotalcites and characterized. When CeO2 was incorporated they showed a very good SO(x) absorption as FCC SO(x) additives, but their regeneration capacity was limited. Different transition metal oxides were tried as co-catalysts, and among them CuO, showed excellent properties to catalyze SO2 oxidation as well as catalyst regeneration. The SO(x) catalyst was stable when steamed at 750-degrees-C together with FCC catalysts.